1. Field of the Invention
The present invention generally relates to energy management systems of a vehicle, in more particularly to energy management systems of a hybrid-electric vehicle.
2. Description of the Known Technology
A hybrid-electric vehicle uses an electric motor in conjunction with a conventional internal combustion engine to create torque to drive its wheels. When the driver of the hybrid-electric vehicle applies the brakes, the hybrid-electric vehicle reverses the function of the electric motor, thus, turning the electric motor into an electric generator. As the hybrid-electric vehicle approaches the stop, the wheels of the hybrid-electric vehicle, in conjunction with the electric motor acting as an electric generator, generate a pulse of electrical power. This pulse of electrical power is stored in an energy storage device such as a capacitor or battery and later used to drive the wheels and/or power the vehicle accessories, such as a heating, ventilation and air conditioning (“HVAC”) system. However, because of the nature of the pulse, when storing the electrical power, some of the electrical power is lost due to parasitic losses.
The electric motor, acting as an electric generator, is not the only source of electrical power in a hybrid-electric vehicle. For example, an alternator and heat capture devices, such as thermoelectric devices placed on the exhaust of the hybrid-electric vehicle, may be utilized to generate electrical power. This electrical power may be stored in an energy storage device. Similar to the electrical power generated by the electric motor, some of the generated electrical power is lost due to parasitic losses.
When the hybrid-electric vehicle is at a stop, it is common for the hybrid-electric vehicle to shut down its internal combustion engine. However, when the HVAC system of the hybrid-electric vehicle is in operation, the hybrid-electric vehicle may have to drain the energy storage device and/or keep the internal combustion engine operating in order to keep the HVAC system running. These demands will decrease fuel economy.
Therefore, it is desire to provide a more efficient system for providing heating and cooling to the occupant compartment of the hybrid-electric vehicle while maximizing the storage of the pulse of electrical power generated during braking and by the other electrical power generated by the hybrid-electric vehicle.